Oil found naturally on human skin can "trap" large amounts of indoor ozone, then "spit" it out in the form of chemicals that may irritate the skin and the lungs, new research suggests.
"They are saying that compounds on the skin react to the ozone and cause more irritation to the skin," explained one expert, Rajat Sethi, an assistant professor of pharmaceutical sciences at Texas A&M Health Science Centre's Irma Lerma Rangel College of Pharmacy in Kingsville. "They have identified those compounds."
But the findings are not cause for major concern yet, according to the study, which is published in the Proceedings of the National Academies of Science.
"I would say this is not very alarming at this point," said study co-lead author Charles J Weschler, an adjunct professor at the University of Medicine & Dentistry of New Jersey in Piscataway. "This chemistry has been going on since the dawn of man. As long as humans have existed, they've existed with ozone, and this chemistry has been occurring," said Weschler, who is also a member of the faculty of the Technical University of Denmark in Copenhagen. He wrote the paper with Armin Wisthaler of Leopold-Franzens University, Innsbruck, Austria.
Little known about indoor ozone
While copious amounts of research have pointed to the negative health effects of outdoor ozone, little is known about indoor ozone or ground-level ozone, especially about its effects on humans.
"We're talking about ozone that people breathe, that people come in contact with, as opposed to ozone up in the stratosphere that protects us from the sun," Weschler explained.
Ozone can travel indoors through ventilation systems and open windows, or it can "sweat" off from office equipment, such as poorly working photocopiers or laser printers.
More common than outdoor ozone
"The US Environmental Protection Agency has claimed that indoor ozone exposure may be 100 times more than outdoor exposure," noted Sethi, who presented a paper at a recent American Heart Association meeting that linked outdoor ozone with an increased risk of ischemic attack and angina.
In their study, Weschler and Wisthaler used "proton transfer reaction-mass spectrometry" to analyse compounds released into the air by the interaction of human skin oil and ozone.
When squalene, the most common fat and antioxidant found on the human skin, from just one person interacted with ozone, this could reduce ozone concentrations in a small room by 10% to 25%, the team found.
By-products of this skin-ozone interaction are later released back into the environment.
"Some of these products are benign, something like acetone or fingernail-polish remover. Some of these compounds have not been identified before in terms of this chemistry, but we don't expect them to pose much of a health concern simply because of their structure," Weschler said. On the other hand, "some of these compounds may be a health concern, but toxicity studies have yet to be done," he added.
Besides the skin, reactions occur on objects where squalene was left by a person's touch, such as furniture or computer equipment.
The research also revealed that squalene and not vitamin E, as was previously thought, is the main antioxidant protecting the skin from ozone. "Squalene has been doing the heavy lifting when it comes to protecting us from the ozone," Wechsler said.
"Some of these products [resulting from the interaction] we inhale and some stay on our skin," he added. "Toxicologists will be looking more closely at what some of the potential health effects are."
Harmful effects of ozone
One expert noted that the latest research sheds more light on ozone's harmful effects.
"Ozone by itself is harmful straight out, and we've known for some time that ozone indoors reacts with a variety of things," said Janice Nolen, assistant vice president of national policy and advocacy at the American Lung Association. This study "tells us more about how ozone can affect us and reinforces why we don't want ozone indoors," she said.
Nolen advised against using products that produce ozone, such as air-purifying devices. "If it's a mechanism with a filter of some kind, then you're not going to be producing ozone," she said. "If you're using something that uses electric static or a chemical process, the odds are that you're going to be producing ozone."
But even filtering, she added, "is limited in its ability to help clean up indoor air." – (Amanda Gardner/HealthDay News, August 2009)